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Zhang WT, Chao THH, Yang Y, Wang TW, Lee SH, Oyarzabal EA, Zhou J, Nonneman R, Pegard NC, Zhu H, Cui G, Shih YYI. Spectral fiber photometry derives hemoglobin concentration changes for accurate measurement of fluorescent sensor activity. CELL REPORTS METHODS 2022; 2:100243. [PMID: 35880016 PMCID: PMC9308135 DOI: 10.1016/j.crmeth.2022.100243] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 04/08/2022] [Accepted: 06/08/2022] [Indexed: 12/22/2022]
Abstract
Fiber photometry is an emerging technique for recording fluorescent sensor activity in the brain. However, significant hemoglobin absorption artifacts in fiber photometry data may be misinterpreted as sensor activity changes. Because hemoglobin exists widely in the brain, and its concentration varies temporally, such artifacts could impede the accuracy of photometry recordings. Here we present use of spectral photometry and computational methods to quantify photon absorption effects by using activity-independent fluorescence signals, which can be used to derive oxy- and deoxy-hemoglobin concentration changes. Although these changes are often temporally delayed compared with the fast-responding fluorescence spikes, we found that erroneous interpretation may occur when examining pharmacology-induced sustained changes and that sometimes hemoglobin absorption could flip the GCaMP signal polarity. We provide hemoglobin-based correction methods to restore fluorescence signals and compare our results with other commonly used approaches. We also demonstrated the utility of spectral fiber photometry for delineating regional differences in hemodynamic response functions.
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Affiliation(s)
- Wei-Ting Zhang
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Tzu-Hao Harry Chao
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Yue Yang
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Tzu-Wen Wang
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Sung-Ho Lee
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Esteban A. Oyarzabal
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jingheng Zhou
- In Vivo Neurobiology Group, Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC 27709, USA
| | - Randy Nonneman
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nicolas C. Pegard
- Department of Applied Physical Sciences, UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hongtu Zhu
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Guohong Cui
- In Vivo Neurobiology Group, Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC 27709, USA
| | - Yen-Yu Ian Shih
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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2
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Kisler K, Lazic D, Sweeney MD, Plunkett S, Khatib ME, Vinogradov SA, Boas DA, Sakadžić S, Zlokovic BV. In vivo imaging and analysis of cerebrovascular hemodynamic responses and tissue oxygenation in the mouse brain. Nat Protoc 2018; 13:1377-1402. [PMID: 29844521 PMCID: PMC6402338 DOI: 10.1038/nprot.2018.034] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cerebrovascular dysfunction has an important role in the pathogenesis of multiple brain disorders. Measurement of hemodynamic responses in vivo can be challenging, particularly as techniques are often not described in sufficient detail and vary between laboratories. We present a set of standardized in vivo protocols that describe high-resolution two-photon microscopy and intrinsic optical signal (IOS) imaging to evaluate capillary and arteriolar responses to a stimulus, regional hemodynamic responses, and oxygen delivery to the brain. The protocol also describes how to measure intrinsic NADH fluorescence to understand how blood O2 supply meets the metabolic demands of activated brain tissue, and to perform resting-state absolute oxygen partial pressure (pO2) measurements of brain tissue. These methods can detect cerebrovascular changes at far higher resolution than MRI techniques, although the optical nature of these techniques limits their achievable imaging depths. Each individual procedure requires 1-2 h to complete, with two to three procedures typically performed per animal at a time. These protocols are broadly applicable in studies of cerebrovascular function in healthy and diseased brain in any of the existing mouse models of neurological and vascular disorders. All these procedures can be accomplished by a competent graduate student or experienced technician, except the two-photon measurement of absolute pO2 level, which is better suited to a more experienced, postdoctoral-level researcher.
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Affiliation(s)
- Kassandra Kisler
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089
| | - Divna Lazic
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089
- Department of Neurobiology, Institute for Biological Research, University of Belgrade, Belgrade, Republic of Serbia
| | - Melanie D. Sweeney
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089
| | - Shane Plunkett
- Departments of Biochemistry and Biophysics and of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - Mirna El Khatib
- Departments of Biochemistry and Biophysics and of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - Sergei A. Vinogradov
- Departments of Biochemistry and Biophysics and of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - David A. Boas
- Optics Division, MGH/HMS/MIT Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 149 13th Street, Charlestown, MA 02129
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215
| | - Sava Sakadžić
- Optics Division, MGH/HMS/MIT Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 149 13th Street, Charlestown, MA 02129
| | - Berislav V. Zlokovic
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089
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3
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Brain Tissue PO 2 Measurement During Normoxia and Hypoxia Using Two-Photon Phosphorescence Lifetime Microscopy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 977:149-153. [PMID: 28685439 DOI: 10.1007/978-3-319-55231-6_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Key to the understanding of the principles of physiological and structural acclimatization to changes in the balance between energy supply (represented by substrate and oxygen delivery, and mitochondrial oxidative phosphorylation) and energy demand (initiated by neuronal activity) is to determine the controlling variables, how they are sensed and the mechanisms initiated to maintain the balance. The mammalian brain depends completely on continuous delivery of oxygen to maintain its function. We hypothesized that tissue oxygen is the primary sensed variable. In this study two-photon phosphorescence lifetime microscopy (2PLM) was used to determine and define the tissue oxygen tension field within the cerebral cortex of mice to a cortical depth of between 200-250 μm under normoxia and acute hypoxia (FiO2 = 0.10). High-resolution images can provide quantitative distributions of oxygen and intercapillary oxygen gradients. The data are best appreciated by quantifying the distribution histogram that can then be used for analysis. For example, in the brain cortex of a mouse, at a depth of 200 μm, tissue oxygen tension was mapped and the distribution histogram was compared under normoxic and mild hypoxic conditions. This powerful method can provide for the first time a description of the delivery and availability of brain oxygen in vivo.
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4
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Yaseen MA, Sutin J, Wu W, Fu B, Uhlirova H, Devor A, Boas DA, Sakadžić S. Fluorescence lifetime microscopy of NADH distinguishes alterations in cerebral metabolism in vivo. BIOMEDICAL OPTICS EXPRESS 2017; 8:2368-2385. [PMID: 28663879 PMCID: PMC5480486 DOI: 10.1364/boe.8.002368] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 05/06/2023]
Abstract
Evaluating cerebral energy metabolism at microscopic resolution is important for comprehensively understanding healthy brain function and its pathological alterations. Here, we resolve specific alterations in cerebral metabolism in vivo in Sprague Dawley rats utilizing minimally-invasive 2-photon fluorescence lifetime imaging (2P-FLIM) measurements of reduced nicotinamide adenine dinucleotide (NADH) fluorescence. Time-resolved fluorescence lifetime measurements enable distinction of different components contributing to NADH autofluorescence. Ostensibly, these components indicate different enzyme-bound formulations of NADH. We observed distinct variations in the relative proportions of these components before and after pharmacological-induced impairments to several reactions involved in glycolytic and oxidative metabolism. Classification models were developed with the experimental data and used to predict the metabolic impairments induced during separate experiments involving bicuculline-induced seizures. The models consistently predicted that prolonged focal seizure activity results in impaired activity in the electron transport chain, likely the consequence of inadequate oxygen supply. 2P-FLIM observations of cerebral NADH will help advance our understanding of cerebral energetics at a microscopic scale. Such knowledge will aid in our evaluation of healthy and diseased cerebral physiology and guide diagnostic and therapeutic strategies that target cerebral energetics.
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Affiliation(s)
- Mohammad A. Yaseen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Jason Sutin
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Weicheng Wu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Buyin Fu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Hana Uhlirova
- Department of Neurosciences and Radiology, UC San Diego, La Jolla, CA, USA
- Current affiliation: Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | - Anna Devor
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Department of Neurosciences and Radiology, UC San Diego, La Jolla, CA, USA
| | - David A. Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Sava Sakadžić
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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5
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Zanello M, Poulon F, Pallud J, Varlet P, Hamzeh H, Abi Lahoud G, Andreiuolo F, Ibrahim A, Pages M, Chretien F, Di Rocco F, Dezamis E, Nataf F, Turak B, Devaux B, Abi Haidar D. Multimodal optical analysis discriminates freshly extracted human sample of gliomas, metastases and meningiomas from their appropriate controls. Sci Rep 2017; 7:41724. [PMID: 28150726 PMCID: PMC5288720 DOI: 10.1038/srep41724] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/23/2016] [Indexed: 01/20/2023] Open
Abstract
Delineating tumor margins as accurately as possible is of primordial importance in surgical oncology: extent of resection is associated with survival but respect of healthy surrounding tissue is necessary for preserved quality of life. The real-time analysis of the endogeneous fluorescence signal of brain tissues is a promising tool for defining margins of brain tumors. The present study aims to demonstrate the feasibility of multimodal optical analysis to discriminate fresh samples of gliomas, metastases and meningiomas from their appropriate controls. Tumor samples were studied on an optical fibered endoscope using spectral and fluorescence lifetime analysis and then on a multimodal set-up for acquiring spectral, one and two-photon fluorescence images, second harmonic generation signals and two-photon fluorescence lifetime datasets. The obtained data allowed us to differentiate healthy samples from tumor samples. These results confirmed the possible clinical relevance of this real-time multimodal optical analysis. This technique can be easily applied to neurosurgical procedures for a better delineation of surgical margins.
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Affiliation(s)
- Marc Zanello
- IMNC Laboratory, UMR 8165-CNRS/IN2P3, Paris-Saclay university, 91405 Orsay, France.,Neurosurgery Department, Sainte-Anne Hospital, France.,Paris Descartes University, Paris, France
| | - Fanny Poulon
- IMNC Laboratory, UMR 8165-CNRS/IN2P3, Paris-Saclay university, 91405 Orsay, France
| | - Johan Pallud
- Neurosurgery Department, Sainte-Anne Hospital, France.,Paris Descartes University, Paris, France
| | - Pascale Varlet
- Paris Descartes University, Paris, France.,Neuropathology Department, Sainte-Anne Hospital, France
| | - H Hamzeh
- Center of Advanced European Studies and Research (caesar), 53175 Bonn, Germany
| | - Georges Abi Lahoud
- Neurosurgery Department, Sainte-Anne Hospital, France.,Paris Descartes University, Paris, France
| | - Felipe Andreiuolo
- Paris Descartes University, Paris, France.,Neuropathology Department, Sainte-Anne Hospital, France
| | - Ali Ibrahim
- IMNC Laboratory, UMR 8165-CNRS/IN2P3, Paris-Saclay university, 91405 Orsay, France
| | - Mélanie Pages
- Paris Descartes University, Paris, France.,Neuropathology Department, Sainte-Anne Hospital, France
| | - Fabrice Chretien
- Paris Descartes University, Paris, France.,Neuropathology Department, Sainte-Anne Hospital, France
| | | | - Edouard Dezamis
- Neurosurgery Department, Sainte-Anne Hospital, France.,Paris Descartes University, Paris, France
| | - François Nataf
- Neurosurgery Department, Sainte-Anne Hospital, France.,Paris Descartes University, Paris, France
| | - Baris Turak
- Neurosurgery Department, Sainte-Anne Hospital, France.,Paris Descartes University, Paris, France
| | - Bertrand Devaux
- Neurosurgery Department, Sainte-Anne Hospital, France.,Paris Descartes University, Paris, France
| | - Darine Abi Haidar
- IMNC Laboratory, UMR 8165-CNRS/IN2P3, Paris-Saclay university, 91405 Orsay, France.,Paris Diderot University, Sorbonne Paris Cité, F-75013, Paris, France
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6
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Pericyte degeneration leads to neurovascular uncoupling and limits oxygen supply to brain. Nat Neurosci 2017; 20:406-416. [PMID: 28135240 PMCID: PMC5323291 DOI: 10.1038/nn.4489] [Citation(s) in RCA: 328] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 12/30/2016] [Indexed: 12/11/2022]
Abstract
Pericytes are perivascular mural cells of brain capillaries that are positioned centrally within the neurovascular unit between endothelial cells, astrocytes and neurons. This unique position allows them to play a major role in regulating key neurovascular functions of the brain. The role of pericytes in the regulation of cerebral blood flow (CBF) and neurovascular coupling remains, however, debatable. Using loss-of-function pericyte-deficient mice, here we show that pericyte degeneration diminishes global and individual capillary CBF responses to neuronal stimulus resulting in neurovascular uncoupling, reduced oxygen supply to brain and metabolic stress. We show that these neurovascular deficits lead over time to impaired neuronal excitability and neurodegenerative changes. Thus, pericyte degeneration as seen in neurological disorders such as Alzheimer’s disease may contribute to neurovascular dysfunction and neurodegeneration associated with human disease.
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7
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8
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Bilan DS, Belousov VV. Genetically encoded probes for NAD +/NADH monitoring. Free Radic Biol Med 2016; 100:32-42. [PMID: 27387770 DOI: 10.1016/j.freeradbiomed.2016.06.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/04/2016] [Accepted: 06/18/2016] [Indexed: 12/18/2022]
Abstract
NAD+ and NADH participate in many metabolic reactions. The NAD+/NADH ratio is an important parameter reflecting the general metabolic and redox state of different types of cells. For a long time, in situ and in vivo NAD+/NADH monitoring has been hampered by the lack of suitable tools. The recent development of genetically encoded indicators based on fluorescent proteins linked to specific nucleotide-binding domains has already helped to address this monitoring problem. In this review, we will focus on four available indicators: Peredox, Frex family probes, RexYFP and SoNar. Each indicator has advantages and limitations. We will also discuss the most important points that should be considered when selecting a suitable indicator for certain experimental conditions.
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Affiliation(s)
- Dmitry S Bilan
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
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9
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Sakadžić S, Lee J, Boas DA, Ayata C. High-resolution in vivo optical imaging of stroke injury and repair. Brain Res 2015; 1623:174-92. [PMID: 25960347 PMCID: PMC4569527 DOI: 10.1016/j.brainres.2015.04.044] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 12/15/2022]
Abstract
Central nervous system (CNS) function and dysfunction are best understood within a framework of interactions between neuronal, glial and vascular compartments comprising the neurovascular unit (NVU), all of which contribute to stroke-induced CNS injury, plasticity, repair, and recovery. Recent advances in in vivo optical microscopy have enabled us to observe and interrogate cells and their processes with high spatial resolution in real time and in their natural environment deep in the brain tissue. Here, we review some of these state-of-the-art imaging techniques with an emphasis on imaging the interactions among the constituents of the NVU during ischemic injury and repair in small animal models. This article is part of a Special Issue entitled SI: Cell Interactions In Stroke.
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Affiliation(s)
- Sava Sakadžić
- Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
| | - Jonghwan Lee
- Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - David A Boas
- Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Cenk Ayata
- Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA; Stroke Service and Neuroscience Intensive Care Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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10
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Physiology-based kinetic modeling of neuronal energy metabolism unravels the molecular basis of NAD(P)H fluorescence transients. J Cereb Blood Flow Metab 2015; 35:1494-506. [PMID: 25899300 PMCID: PMC4640339 DOI: 10.1038/jcbfm.2015.70] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 02/19/2015] [Accepted: 03/18/2015] [Indexed: 01/06/2023]
Abstract
Imaging of the cellular fluorescence of the reduced form of nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) is one of the few metabolic readouts that enable noninvasive and time-resolved monitoring of the functional status of mitochondria in neuronal tissues. Stimulation-induced transient changes in NAD(P)H fluorescence intensity frequently display a biphasic characteristic that is influenced by various molecular processes, e.g., intracellular calcium dynamics, tricarboxylic acid cycle activity, the malate-aspartate shuttle, the glycerol-3-phosphate shuttle, oxygen supply or adenosine triphosphate (ATP) demand. To evaluate the relative impact of these processes, we developed and validated a detailed physiologic mathematical model of the energy metabolism of neuronal cells and used the model to simulate metabolic changes of single cells and tissue slices under different settings of stimulus-induced activity and varying nutritional supply of glucose, pyruvate or lactate. Notably, all experimentally determined NAD(P)H responses could be reproduced with one and the same generic cellular model. Our computations reveal that (1) cells with quite different metabolic status may generate almost identical NAD(P)H responses and (2) cells of the same type may quite differently contribute to aggregate NAD(P)H responses recorded in brain slices, depending on the spatial location within the tissue. Our computational approach reconciles different and sometimes even controversial experimental findings and improves our mechanistic understanding of the metabolic changes underlying live-cell NAD(P)H fluorescence transients.
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11
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Richner TJ, Baumgartner R, Brodnick SK, Azimipour M, Krugner-Higby LA, Eliceiri KW, Williams JC, Pashaie R. Patterned optogenetic modulation of neurovascular and metabolic signals. J Cereb Blood Flow Metab 2015; 35:140-7. [PMID: 25388678 PMCID: PMC4294407 DOI: 10.1038/jcbfm.2014.189] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 09/26/2014] [Accepted: 09/30/2014] [Indexed: 11/09/2022]
Abstract
The hemodynamic and metabolic response of the cortex depends spatially and temporally on the activity of multiple cell types. Optogenetics enables specific cell types to be modulated with high temporal precision and is therefore an emerging method for studying neurovascular and neurometabolic coupling. Going beyond temporal investigations, we developed a microprojection system to apply spatial photostimulus patterns in vivo. We monitored vascular and metabolic fluorescence signals after photostimulation in Thy1-channelrhodopsin-2 mice. Cerebral arteries increased in diameter rapidly after photostimulation, while nearby veins showed a slower smaller response. The amplitude of the arterial response was depended on the area of cortex stimulated. The fluorescence signal emitted at 450/100 nm and excited with ultraviolet is indicative of reduced nicotinamide adenine dinucleotide, an endogenous fluorescent enzyme involved in glycolysis and the citric acid cycle. This fluorescence signal decreased quickly and transiently after optogenetic stimulation, suggesting that glucose metabolism is tightly locked to optogenetic stimulation. To verify optogenetic stimulation of the cortex, we used a transparent substrate microelectrode array to map cortical potentials resulting from optogenetic stimulation. Spatial optogenetic stimulation is a new tool for studying neurovascular and neurometabolic coupling.
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Affiliation(s)
- Thomas J Richner
- Laboratory for Optical and Computational Instrumentation and Department of Biomedical Engineering, University of Wisconsin at Madison, Madison, Wisconsin, USA
| | - Ryan Baumgartner
- Department of Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Sarah K Brodnick
- Laboratory for Optical and Computational Instrumentation and Department of Biomedical Engineering, University of Wisconsin at Madison, Madison, Wisconsin, USA
| | - Mehdi Azimipour
- Department of Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Lisa A Krugner-Higby
- Laboratory for Optical and Computational Instrumentation and Department of Biomedical Engineering, University of Wisconsin at Madison, Madison, Wisconsin, USA
| | - Kevin W Eliceiri
- Laboratory for Optical and Computational Instrumentation and Department of Biomedical Engineering, University of Wisconsin at Madison, Madison, Wisconsin, USA
| | - Justin C Williams
- Laboratory for Optical and Computational Instrumentation and Department of Biomedical Engineering, University of Wisconsin at Madison, Madison, Wisconsin, USA
| | - Ramin Pashaie
- Department of Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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12
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Martin C. Contributions and complexities from the use of in vivo animal models to improve understanding of human neuroimaging signals. Front Neurosci 2014; 8:211. [PMID: 25191214 PMCID: PMC4137227 DOI: 10.3389/fnins.2014.00211] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 07/01/2014] [Indexed: 01/18/2023] Open
Abstract
Many of the major advances in our understanding of how functional brain imaging signals relate to neuronal activity over the previous two decades have arisen from physiological research studies involving experimental animal models. This approach has been successful partly because it provides opportunities to measure both the hemodynamic changes that underpin many human functional brain imaging techniques and the neuronal activity about which we wish to make inferences. Although research into the coupling of neuronal and hemodynamic responses using animal models has provided a general validation of the correspondence of neuroimaging signals to specific types of neuronal activity, it is also highlighting the key complexities and uncertainties in estimating neural signals from hemodynamic markers. This review will detail how research in animal models is contributing to our rapidly evolving understanding of what human neuroimaging techniques tell us about neuronal activity. It will highlight emerging issues in the interpretation of neuroimaging data that arise from in vivo research studies, for example spatial and temporal constraints to neuroimaging signal interpretation, or the effects of disease and modulatory neurotransmitters upon neurovascular coupling. We will also give critical consideration to the limitations and possible complexities of translating data acquired in the typical animals models used in this area to the arena of human fMRI. These include the commonplace use of anesthesia in animal research studies and the fact that many neuropsychological questions that are being actively explored in humans have limited homologs within current animal models for neuroimaging research. Finally we will highlighting approaches, both in experimental animals models (e.g. imaging in conscious, behaving animals) and human studies (e.g. combined fMRI-EEG), that mitigate against these challenges.
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Affiliation(s)
- Chris Martin
- Department of Psychology, The University of Sheffield Sheffield, UK
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13
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Niklass S, Stoyanov S, Garz C, Bueche CZ, Mencl S, Reymann K, Heinze HJ, Carare RO, Kleinschnitz C, Schreiber S. Intravital imaging in spontaneously hypertensive stroke-prone rats-a pilot study. EXPERIMENTAL & TRANSLATIONAL STROKE MEDICINE 2014; 6:1. [PMID: 24461046 PMCID: PMC3996193 DOI: 10.1186/2040-7378-6-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/19/2014] [Indexed: 12/02/2022]
Abstract
Background There is growing evidence that endothelial failure and subsequent blood brain barrier (BBB) breakdown initiate cerebral small vessel disease (CSVD) pathology. In spontaneously hypertensive stroke-prone rats (SHRSP) endothelial damage is indicated by intraluminal accumulations of erythrocytes (erythrocyte thrombi) that are not observed with current magnetic resonance imaging techniques. Two-photon microscopy (2 PM) offers the potential for real-time direct detection of the small vasculature. Thus, within this pilot study we investigated the sensitivity of 2 PM to detect erythrocyte thrombi expressing initiating CSVD phenomena in vivo. Methods Eight SHRSP and 13 Wistar controls were used for in vivo imaging and subsequent histology with haematoxylin-eosin (HE). For 2 PM, cerebral blood vessels were labeled by fluorescent Dextran (70 kDa) applied intraorbitally. The correlation between vascular erythrocyte thrombi observed by 2 PM and HE-staining was assessed. Artificial surgical damage and parenchymal Dextran distribution were analyzed postmortem. Results Dextran was distributed within the small vessel walls and co-localized with IgG. Artificial surgical damage was comparable between SHRSP and Wistar controls and mainly affected the small vasculature. In fewer than 20% of animals there was correlation between erythrocyte thrombi as observed with 2 PM and histologically with HE. Conclusions Contrary to our initial expectations, there was little agreement between intravital 2 PM imaging and histology for the detection of erythrocyte thrombi. Two-photon microscopy is a valuable technique that complements but does not replace the value of conventional histology.
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Affiliation(s)
- Solveig Niklass
- Department of Neurology, Otto-von-Guericke-University, Leipziger Strasse 44, 39120 Magdeburg, Germany.
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14
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Functional Imaging of Cerebral Oxygenation with Intrinsic Optical Contrast and Phosphorescent Probes. NEUROMETHODS 2014. [DOI: 10.1007/978-1-62703-785-3_14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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15
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Yaseen MA, Sakadžić S, Wu W, Becker W, Kasischke KA, Boas DA. In vivo imaging of cerebral energy metabolism with two-photon fluorescence lifetime microscopy of NADH. BIOMEDICAL OPTICS EXPRESS 2013; 4:307-21. [PMID: 23412419 PMCID: PMC3567717 DOI: 10.1364/boe.4.000307] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/17/2013] [Accepted: 01/17/2013] [Indexed: 05/04/2023]
Abstract
Minimally invasive, specific measurement of cellular energy metabolism is crucial for understanding cerebral pathophysiology. Here, we present high-resolution, in vivo observations of autofluorescence lifetime as a biomarker of cerebral energy metabolism in exposed rat cortices. We describe a customized two-photon imaging system with time correlated single photon counting detection and specialized software for modeling multiple-component fits of fluorescence decay and monitoring their transient behaviors. In vivo cerebral NADH fluorescence suggests the presence of four distinct components, which respond differently to brief periods of anoxia and likely indicate different enzymatic formulations. Individual components show potential as indicators of specific molecular pathways involved in oxidative metabolism.
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Affiliation(s)
- Mohammad A. Yaseen
- Optics Division, MGH/MIT/HMS Athinoula A. Martinos Center for
Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Charlestown,
Massachusetts 02129, USA
| | - Sava Sakadžić
- Optics Division, MGH/MIT/HMS Athinoula A. Martinos Center for
Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Charlestown,
Massachusetts 02129, USA
| | - Weicheng Wu
- Optics Division, MGH/MIT/HMS Athinoula A. Martinos Center for
Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Charlestown,
Massachusetts 02129, USA
| | - Wolfgang Becker
- Becker & Hickl GmbH, Nahmitzer Damm 30, 12277 Berlin,
Germany
| | - Karl A. Kasischke
- Department of Neurology, University of Ulm Medical Center, Oberer
Eselsberg 45, 89075 Ulm, Germany
| | - David A. Boas
- Optics Division, MGH/MIT/HMS Athinoula A. Martinos Center for
Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Charlestown,
Massachusetts 02129, USA
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